1. Field of the Invention
This invention relates to a touch sensor assembly and a method of making the same, more particularly to a method of making a touch sensor assembly having a conductor layer formed by sputtering a metallic target in the presence of a reactive gas.
2. Description of the Related Art
FIG. 1 illustrates a touch sensor assembly of a conventional touch panel 1 for assembly with a display panel (not shown) to form a touch display. The touch sensor assembly includes a transparent glass substrate 11, a plurality of transparent conductive trace elements 12 spaced apart from each other, a transparent insulator 13 formed on the substrate 11 and covering a portion of the conductive trace elements 12, a plurality of conductive bridging lines 14 (only one bridging line is shown for the sake of clarity), and a transparent protective layer 15 formed on the bridging lines 14, the insulator 13 and the conductive trace elements 12. Each of the bridging lines 14 bridges two corresponding ones of the conductive trace elements 12 so as to form a touch sensor region on the substrate 11.
In order to obtain high touch sensitivity, the electrical resistance of the bridging lines 14 must be sufficiently low. Hence, the bridging lines 14 are normally made from metal, such as aluminum (Al), copper (Cu), Al-based alloys, and Cu-based alloys. In addition, any impurities present in the bridging lines 14 can cause a considerable increase in the electrical resistance thereof. Hence, formation of the bridging lines 14 is normally conducted by sputtering a metallic target in the presence of argon so as to prevent impurities from entering into the bridging lines 14. However, the bridging lines 14 thus formed have a high reflectivity and exhibit metallic luster, which is undesirable for the viewer when viewing the touch panel and which adversely affects the viewing quality of the touch panel. Hence, there is a need to reduce the visibility of the bridging lines 14 for achieving a better viewing quality.